Slepton and squark production and decay inep collisions at the LHC

We present a detailed study of and and the subsequent decays of , , and at the LHC . We explore the relevant supersymmetry parameter range. We calculate the cross sections as well as the rates for interesting signatures such as the production of one or two leptons on the lepton side.     

Gauge invariance and renormalization schemes in quantum chromodynamics

A general analysis of the Slavnov-Taylor identity connecting the triple gluon and ghost-ghost-gluon vertices and its consequences for two momentum subtraction (symmetric and asymmetric) renormalization schemes are given. It is shown that in the asymmetric scheme proposed in this paper the relation follows directly from the identity for a simple and natural definition of the renormalization constants. Explicit one-loop expressions for the renormalization constants in an arbitrary covariant gauge, including quark masses are given in support of the general analysis.     

Modified Weyl theory and extended elementary objects

To represent extension of objects in particle physics, a modified Weyl theory is used by gauging the curvature radius of the local fibers in a soldered bundle over space-time possessing a homogeneous space G/H of the (4, 1)-de Sitter group G as fiber. Objects with extension determined by a fundamental length parameter R₀ appear as islands D_(i) in space-time characterized by a geometry of the Cartan-Weyl type (i.e., involving torsion and modified Weyl degrees of freedom). Farther away from the domains D_(i), space-time is identified with the pseudo-Riemannian space of general relativity. Extension and symmetry breaking are described by a set of additional fields ( , given as a section on an associated bundle over space-time B with structural group = G D(1), where D(1) is the dilation group. Field equations for the quantities defining the underlying bundle geometry and for the fields are established involving matter source currents derived from a generalized spinor wave function. Einstein's equations for the metric are regarded as the part of the -gauge theory related to the Lorentz subgroup H of G exhibiting thereby the broken nature of the -symmetry for regions outside the domains D_(i).Talk presented at the International Conference on Field Theory and General Relativity held at Utah State University, Logan, Utah, June 26–July 2, 1988.     

Algebraically special left-flat spaces and their associated space-times

In a recent paper it was shown how to construct, under certain circumstances, asymptotic (Newman-Unti) series expansions for the spin-coefficient variables for real space-times from data obtained from a given left-flat space in an appropriate frame. If these expansions represent asymptotically flat space-times the latter have the given left-flat space as their H space. The method was described in a frame in which the asymptotic left-shear was zero whereas was not. For the discussion of algebraically special left-flat spaces it is more convenient to have vanish and remain nonzero. In this paper we determine all algebraically special left-flat spaces with diverging rays, utilizing Penrose's conformal technique, and then show in detail how to find the “initial data” for the construction of asymptotic series expansions for the corresponding real space-times.     

Precise calculation of the dynamical exponent of two-dimensional percolation

We report numerical data obtained on the special-purpose computer PERCOLA for the exponent of the electrical conductivity of 2D percolation. The extrapolation yields and a correction to the scaling exponent=1.2±0.2.     

Space tensors in general relativity I: Spatial tensor algebra and analysis

A pair (M, Γ) is defined as a Riemannian manifold M of normal hyperbolic type carrying a distinguished time-like congruence Γ. The spatial tensor algebraD associated with the pair (M, Γ) is discussed. A general definition of the concept of spatial tensor analysis over (M, Γ) is then proposed. Basically, this includes a spatial covariant differentiation and a time-derivative , both acting onD and commuting with the process of raising and lowering the tensor indices. The torsion tensor fields of the pair are discussed, as well as the corresponding structural equations. The existence of a distinguished spatial tensor analysis over (M, Γ) is finally established, and the resulting mathematical structure is examined in detail. This work was assisted by funds from the C.N.R. under the aegis of the activity of the National Group for Mathematical Physics.     

Construction of simple approximants for the structure factor and magnetization for the simple cubic Ising model

A renormalization group method is used to construct approximants for the magnetization,m, and the static structure factor, (q), for the simple cubic Ising model. Using the best values for the thermal critical index, the transition temperature, and the nearest-neighbor correlation function as input, we obtain recursion relations form and (q) which lead to reasonable results over a wide range of temperatures and wave numbers.     

Resonance CARS detection of SiC2 as reaction intermediate in IR laser synthesis of SiC from SiH4/hydrocarbon mixtures

Coherent anti-Stokes Raman Scattering has been employed to investigate gas-phase reactions between SiH₄ and small hydrocarbons leading to formation of SiC powder. SiC₂ has been identified as reaction intermediate, due to the occurrence of resonance enhanced CARS coupling vibrational leavels in the ground and first electronically excited state. The rich structure observed in the range 4480 Å<_AS<4650 Å is assigned to SiC₂ taking into account the cyclic geometry of this species and revising former data on electronic transitions.ENEA Guest     

Isospectral Hamiltonian flows in finite and infinite dimensions

The approach to isospectral Hamiltonian flow introduced in part I is further developed to include integration of flows with singular spectral curves. The flow on finite dimensional Ad^*-invariant Poisson submanifolds of the dual of the positive part of the loop algebra is obtained through a generalization of the standard method of linearization on the Jacobi variety of the invariant spectral curveS. These curves are embedded in the total space of a line bundleTP ₁(C), allowing an explicit analysis of singularities arising from the structure of the image of a moment map from the space of rank-r deformations of a fixedN×N matrixA. It is shown how the linear flow of line bundles over a suitably desingularized curve may be used to determine both the flow of matricial polynomialsL() and the Hamiltonian flow in the spaceM _N,r×M_N,r in terms of -functions. The resulting flows are proved to be completely integrable. The reductions to subalgebras developed in part I are shown to correspond to invariance of the spectral curves and line bundles under certain linear or anti-linear involutions. The integration of two examples from part I is given to illustrate the method: the Rosochatius system, and the CNLS (coupled non-linear Schrödinger) equation.Research supported in part by the Natural Sciences and Engineering Research Council of Canada and by U.S. Army grant DAA L03-87-K-0110     

On the purification map

The investigation of purifications of factor states has been carried on. It is shown, that any factor state of aC*-algebra admits at most one purification , so one can introduce the purification map . It turns out, that the Powers and Størmer inequality is valid in this general situation.     

CP-violating effects inZ decays to τ leptons

We calculate CP-odd correlations inZ decays to leptons, . These correlations are sensitive to the weak dipole moment of the . With 10⁷ producedZ particles and with observation of the decay channels and v we estimate that can be determined with an accuracy of about (1 s.d.).     

Two-photon predissociative fluorescence of H2O by a KrF laser for concentration and temperature measurement in flames

Two-photon laser-induced predissociative fluorescence (LIPF) of H₂O is examined as a potential measurement technique of H₂O concentration and temperature in flames. Two-photons of 248 nm light from a narrowband KrF laser excite H₂O to the highly predissociative state in a hydrogen-air flame. The subsequent bound-free emission is observed from 400–500 nm in the flame at temperatures of 1000–2000 K and is found to be free of fluorescence interference from other flame species. This LIPF signal is not affected by collisional quenching due to the short lifetime of the predissociative state (2.5 ps). Broadband laser dispersion spectra, narrowband laser dispersion spectra, laser excitation spectra and probability density functions of the H₂O fluorescence are obtained in the hydrogen flame. The H₂O LIPF signal is found to be temperature sensitive and a two-line LIPF technique is needed for concentration and temperature measurement. The accuracy of a two-line LIPF technique for H₂O concentration and temperature measurement is determined.     

Entropy functionals of Kolmogorov-Sinai type and their limit theorems

Two functionals and are introduced forC ^*-dynamical systems with invariant states and stationary channels. It is shown that the Kolmogorov-Sinai-type theorems hold for these functionals and . Our functionals and are set within the framework of quantum information theory and generalize a quantum KS entropy by CNT and the mutual entropy by Ohya.     

A mathematical condition for a sublattice of a propositional system to represent a physical subsystem,with a physical interpretation

We display three equivalent conditions for a sublattice, isomorphic to aP , of the propositional systemP() of a quantum system to be the representation of a physical subsystem (see [1]). These conditions are valid for dim 3. We prove that one of them is still necessary and sufficient if dim <3. A physical interpretation of this condition is given.Wetenschappelijke medewerkers bij het Interuniversitair Instituut voor Kernwetenschappen (in het kader van navorsingsprogramma 21 EN).     

Suppression of electron-phonon interaction in narrow-band crystals

Taking the inelastic nature of the interaction of electrons with acoustic phonons into account is crucial in crystals having a conduction band width Δɛ comparable to the maximum acoustic phonon energy . In view of this, the laws of conservation of energy and wave vector impose stringent constraints on possible electron scattering processes, and single-phonon scattering becomes impossible for . The phonon contribution to the resistance may be negligible, therefore, in narrow-band conductors. Novosibirsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, p. 78–82, August, 1997.     

The nucleon quark distribution amplitude and its influence on theQ 2-behaviour of nucleon form factors

In a re-analysis of nucleon form factors in perturbative quantum chromodynamics we examine the -dependence of the nucleon quark distribution amplitude by means of some model distribution amplitudes. We point out some problems that arise in the determination of the -evolution of the distribution amplitude. Our suggestions to cure these problems are discussed and resulting nucleon quark distribution amplitudes are presented. These give reasonable agreement with the available data for the form factors.Work is supported by Deutsche Forschungsgemeinschaft (Ga 153-13-1) and partially by NATO (0581/87)     

Functional integral via functional equation

Discretization ofp-adic Grassmann-valued -model leads to a hierarchical model with the Hamtilonian given by a nontrivial functional integral over the Grassmann variables. Using renormalization group arguments, we reduce the calculation of this integral to a functional equation. The problem of the convergence of the perturbation expansion of this integral, realized as a small-divisors problem, is investigated.     

Superplasticity in A Zn-1·1 wt. % Al alloy

In the paper the results of the deformation behaviour study in a fine-grained Zn-1·1 wt. % Al alloy are presented. The influence of strain rate ranging from 4·2×10^–5 to 4·2×10^–2 s^–1 on the true stress — true strain curves, ductility and strain rate sensitivity was investigated at temperatures 295 K and 375 K. At both temperatures the superplastic behaviour was observed. The increase in temperature improved the superplastic properties and shifted the region of the superplastic behaviour to higher strain rates. The maximum values of ductilityA=700% and strain rate sensitivity parameter m=0·48 were established at 375 K at strain rates . The true stress — true strain curves were found to be influenced by a grain growth taking place during the deformation. The grain growth was also found to be responsible for significant differences in the parameterm values obtained from the log plots and from the strain rat-changes.     

On the Product of Real Spectral Triples

The product of two real spectral triples and , the first of which is necessarily even, was defined by A.Connes as given by and, in the even-even case, by . Generically it is assumed that the real structure obeys the relations , , , where the -sign table depends on the dimension n modulo 8 of the spectral triple. If both spectral triples obey Connes' >-sign table, it is seen that their product, defined in the straightforward way above, does not necessarily obey this -sign table. In this Letter, we propose an alternative definition of the product real structure such that the -sign table is also satisfied by the product.